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https://www.readbyqxmd.com/read/27759380/ab-initio-thermodynamic-and-thermophysical-properties-of-sodium-metasilicate-na2sio3-and-their-electron-density-and-electron-pair-density-counterparts
#1
Donato Belmonte, Carlo Gatti, Giulio Armando Ottonello, Pascal Richet, Marino Vetuschi Zuccolini
Thermodynamic and thermophysical properties of Na2SiO3 in the Cmc21 structural state are computed ab-initio using the hybrid B3LYP density functional method. The static properties at the athermal limit are first evaluated through a symmetry-preserving relaxation procedure. The thermodynamic properties that depend on vibrational frequencies viz, heat capacities, thermal expansion, thermal derivative of the bulk modulus, thermal correction to internal energy, enthalpy, Gibbs free energy, are then computed in the framework of quasi-harmonic approximation...
October 19, 2016: Journal of Physical Chemistry. A
https://www.readbyqxmd.com/read/27566087/renal-denervation-in-patients-with-resistant-hypertension-assessment-by-3t-renal-23na-mri-preliminary-results
#2
Johannes Budjan, Urs Benck, Alexander Lammert, Melissa M Ong, Miryana Mircheva, Steffen Diehl, Simon Konstandin, Lothar R Schad, Bernhard K Krämer, Stefan O Schoenberg, Stefan Haneder
BACKGROUND/AIM: Renal denervation (RDN) has been considered a promising therapy option for patients suffering from therapy-resistant hypertension. Besides, in blood-pressure regularization, the kidneys play a fundamental role in sodium ((23)Na) homeostasis. This study assesses the effect of RDN on renal (23)Na concentration using (23)Na magnetic resonance imaging (MRI). PATIENTS AND METHODS: Two patients with therapy-resistant hypertension underwent RDN. (23)Na-MRI, (1)H-MRI, including diffusion weighted imaging (DWI), as well as endothelial dysfunction assessment, were performed 1 day prior, as well as 1, 30 and 90 days after RDN...
September 2016: In Vivo
https://www.readbyqxmd.com/read/27391676/functional-differentiation-of-antiporter-like-polypeptides-in-complex-i-a-site-directed-mutagenesis-study-of-residues-conserved-in-mrpa-and-nuol-but-not-in-mrpd-nuom-and-nuon
#3
Eva Sperling, Kamil Górecki, Torbjörn Drakenberg, Cecilia Hägerhäll
It has long been known that the three largest subunits in the membrane domain (NuoL, NuoM and NuoN) of complex I are homologous to each other, as well as to two subunits (MrpA and MrpD) from a Na+/H+ antiporter, Mrp. MrpA and NuoL are more similar to each other and the same is true for MrpD and NuoN. This suggests a functional differentiation which was proven experimentally in a deletion strain model system, where NuoL could restore the loss of MrpA, but not that of MrpD and vice versa. The simplest explanation for these observations was that the MrpA and MrpD proteins are not antiporters, but rather single subunit ion channels that together form an antiporter...
2016: PloS One
https://www.readbyqxmd.com/read/27215093/measurement-of-serum-sodium-and-magnesium-by-inductively-coupled-plasma-mass-spectrometry-with-aluminum-as-internal-standard
#4
Ying Yan, Chuanbao Zhang, Jiangtao Zhang, Tianjiao Zhang, Weiyan Zhou, Jie Zeng, Wenxiang Chen
BACKGROUND: Serum sodium and magnesium are important clinical laboratory tests and accurate testing results are needed for the correct interpretation of the tests. Standardization of serum sodium and magnesium measurements requires simple and reliable reference methods. METHODS: Inductively coupled plasma mass spectrometry (ICP-MS) methods for the measurement of serum sodium and magnesium were developed. Aluminum was used as an internal standard. Serum samples were spiked with the internal standard, digested with 69% nitric acid at 150 degrees C and measured for 23Na/27Al and 24Mg/27Al ratios by ICP-MS...
2016: Clinical Laboratory
https://www.readbyqxmd.com/read/26931131/interface-induced-growth-and-transformation-of-polymer-conjugated-proto-crystalline-phases-in-aluminosilicate-hybrids-a-multiple-quantum-23-na-23-na-mas-nmr-correlation-spectroscopy-study
#5
Jiri Brus, Libor Kobera, Martina Urbanova, Barbora Doušová, Miloslav Lhotka, David Koloušek, Jiří Kotek, Pavel Čuba, Jiri Czernek, Jiří Dědeček
Nanostructured materials typically offer enhanced physicochemical properties because of their large interfacial area. In this contribution, we present a comprehensive structural characterization of aluminosilicate hybrids with polymer-conjugated nanosized zeolites specifically grown at the organic-inorganic interface. The inorganic amorphous Al-O-Si framework is formed by alkali-activated low-temperature transformation of metakaoline, whereas simultaneous copolymerization of organic comonomers creates a secondary epoxide network covalently bound to the aluminosilicate matrix...
March 22, 2016: Langmuir: the ACS Journal of Surfaces and Colloids
https://www.readbyqxmd.com/read/26714113/polymorphism-of-metallic-sodium-under-nanoconfinement
#6
A V Uskov, D Yu Nefedov, E V Charnaya, J Haase, D Michel, Yu A Kumzerov, A V Fokin, A S Bugaev
(23)Na NMR studies of sodium nanoparticles confined to porous glass with the 3.5 nm mean pore size were carried out. The emergence of the second component of the NMR line was observed below 240 K that evidences the occurrence of another modification of metallic sodium. The phase transition temperature is much higher than the martensite transformation temperature in bulk sodium.
January 13, 2016: Nano Letters
https://www.readbyqxmd.com/read/26453681/heterogeneity-of-acute-multiple-sclerosis-lesions-on-sodium-23na-mri
#7
Philipp Eisele, Simon Konstandin, Martin Griebe, Kristina Szabo, Marc E Wolf, Angelika Alonso, Anne Ebert, Julia Serwane, Christina Rossmanith, Michael G Hennerici, Lothar R Schad, Achim Gass
BACKGROUND: Advanced magnetic resonance imaging (MRI) techniques provide a window into pathological processes in multiple sclerosis (MS). Nevertheless, to date only few studies have performed sodium MRI in MS. OBJECTIVES: We analysed total sodium concentration (TSC) in hyperacute, acute and chronic lesions in MS with (23)Na MRI. METHODS: (23)Na MRI and (1)H MRI were performed in 65 MS patients and 10 healthy controls (HC). Mean TSC was quantified in all MS lesions with a diameter of >5 mm and in the normal appearing white and grey matter (NAWM, NAGM)...
July 2016: Multiple Sclerosis: Clinical and Laboratory Research
https://www.readbyqxmd.com/read/25815412/na-ca-intermixing-around-silicate-and-phosphate-groups-in-bioactive-phosphosilicate-glasses-revealed-by-heteronuclear-solid-state-nmr-and-molecular-dynamics-simulations
#8
Renny Mathew, Baltzar Stevensson, Mattias Edén
We characterize the intermixing of network-modifying Na(+)/Ca(2+) ions around the silicate (QSi(n)) and phosphate (QP(n)) tetrahedra in a series of 16 Na2O–CaO–SiO2–P2O5 glasses, whose P content and silicate network connectivity were varied independently. The set includes both bioactive and bioinactive compositions and also encompasses two soda-lime-silicate members devoid of P, as well as two CaO–SiO2 glasses and one Na2O–SiO2–P2O5 glass. The various Si/P↔Na/Ca contacts were probed by molecular dynamics (MD) simulations together with heteronuclear magic-angle-spinning (MAS) nuclear magnetic resonance (NMR) experimentation utilizing (23)Na{(31)P} and (23)Na{(29)Si} REDOR, as well as (31)P{ (23)Na} and (29)Si{(23)Na} REAPDOR...
April 30, 2015: Journal of Physical Chemistry. B
https://www.readbyqxmd.com/read/25730710/pulse-electron-double-resonance-detected-multinuclear-nmr-spectra-of-distant-and-low-sensitivity-nuclei-and-its-application-to-the-structure-of-mn-ii-centers-in-organisms
#9
Eduardo M Bruch, Melissa T Warner, Sébastien Thomine, Leandro C Tabares, Sun Un
The ability to characterize the structure of metal centers beyond their primary ligands is important to understanding their chemistry. High-magnetic-field pulsed electron double resonance detected NMR (ELDOR-NMR) is shown to be a very sensitive approach to measuring the multinuclear NMR spectra of the nuclei surrounding Mn(II) ions. Resolved spectra of intact organisms with resonances arising from (55)Mn, (31)P, (1)H, (39)K, (35)Cl, (23)Na, and (14)N nuclei surrounding Mn(2+) centers were obtained. Naturally abundant cellular (13)C could be routinely measured as well...
October 29, 2015: Journal of Physical Chemistry. B
https://www.readbyqxmd.com/read/25712045/intermolecular-interaction-and-the-extended-wormlike-chain-conformation-of-chitin-in-naoh-urea-aqueous-solution
#10
Yan Fang, Bo Duan, Ang Lu, Maili Liu, Huili Liu, Xiaojuan Xu, Lina Zhang
The intra- and intermolecular interactions of chitin in NaOH/urea aqueous system were studied by a combination of NMR measurements (including (13)C NMR, (23)Na NMR, and (15)N NMR) and differential scanning calorimetry. The results revealed that the NaOH and chitin formed a hydrogen-bonded complex that was surrounded by the urea hydrates to form a sheath-like structure, leading to the good dissolution. The optimal concentration range, in which chitin was molecularly dispersed in NaOH/urea aqueous, was found to investigate the chain conformation in the dilute solution with a combination of static and dynamic light scattering...
April 13, 2015: Biomacromolecules
https://www.readbyqxmd.com/read/25606557/imaging-of-articular-cartilage-current-concepts
#11
Mario Ronga, Gloria Angeretti, Sergio Ferraro, Giovanni DE Falco, Eugenio A Genovese, Paolo Cherubino
Magnetic resonance imaging (MRI) is the gold standard method for non-invasive assessment of joint cartilage, providing information on the structure, morphology and molecular composition of this tissue. There are certain minimum requirements for a MRI study of cartilage tissue: machines with a high magnetic field (> 1.5 Tesla); the use of surface coils; and the use of T2-weighted, proton density-weighted fast-spin echo (T2 FSE-DP) and 3D fat-suppressed T1-weighted gradient echo (3D-FS T1W GRE) sequences. For better contrast between the different joint structures, MR arthography is a method that can highlight minimal fibrillation or fractures of the articular surface and allow evaluation of the integrity of the native cartilage-repair tissue interface...
July 2014: Joints
https://www.readbyqxmd.com/read/25462793/anatomically-weighted-second-order-total-variation-reconstruction-of-23na-mri-using-prior-information-from-1h-mri
#12
Christine Gnahm, Armin M Nagel
Sodium ((23)Na) MRI is a noninvasive tool to assess cell viability, which is linked to the total tissue sodium concentration (TSC). However, due to low in vivo concentrations, (23)Na MRI suffers from low signal-to-noise ratio (SNR) and limited spatial resolution. As a result, image quality is compromised by Gibbs ringing artifacts and partial volume effects. An iterative reconstruction algorithm that incorporates prior information from (1)H MRI is developed to reduce partial volume effects and to increase the SNR in non-proton MRI...
January 15, 2015: NeuroImage
https://www.readbyqxmd.com/read/24843809/commentary-on-four-recently-published-papers-on-chronic-pain-and-spinal-surgery
#13
Ronald Pawl
This commentary evaluates four articles dealing with chronic pain from very different perspectives. The first paper by Tsantoulas and McMahon entitled "Opening paths to novel analgesics: the role of potassium channels in chronic pain" evaluates the membrane neurochemistry of the neural cells governing the transmission of pain impulses in the spinal cord and trigeminal systems. As potassium membrane potentials diminish excitability in the nociceptive pain pathways, damage to these pathways may result in excessive transmission of impulses that contribute to "chronic pain"...
2014: Surgical Neurology International
https://www.readbyqxmd.com/read/24668008/quantitative-sodium-mr-imaging-of-native-versus-transplanted-kidneys-using-a-dual-tuned-proton-sodium-1h-23na-coil-initial-experience
#14
COMPARATIVE STUDY
Chan Hong Moon, Alessandro Furlan, Jung-Hwan Kim, Tiejun Zhao, Ron Shapiro, Kyongtae Ty Bae
OBJECTIVES: To compare sodium ((23)Na) characteristics between native and transplanted kidneys using dual-tuned proton ((1)H)/sodium MRI. METHODS: Six healthy volunteers and six renal transplant patients (3 normal function, 3 acute allograft rejection) were included. Proton/sodium MRI was obtained at 3 T using a dual-tuned coil. Signal to noise ratio (SNR), sodium concentration ([(23)Na]) and cortico-medullary sodium gradient (CMSG) were measured. Reproducibility of [(23)Na] measurement was also tested...
June 2014: European Radiology
https://www.readbyqxmd.com/read/24530955/two-pulse-biexponential-weighted-23na-imaging
#15
Nadia Benkhedah, Peter Bachert, Armin M Nagel
A new method is proposed for acquiring 3D biexponential-weighted sodium images with two instead of three RF pulses to allow for shorter repetition time at high magnetic fields (B0≥7 T) and reduced SAR. The second pulse converts single- into triple-quantum coherences in regions containing sodium ions which are restricted in mobility. Since only single-quantum coherences can be detected, an image acquired after the second pulse is intrinsically single-quantum-filtered and can be used to generate a biexponential-weighted sodium image by a weighted subtraction with the spin-density-weighted image acquired between the pulses...
March 2014: Journal of Magnetic Resonance
https://www.readbyqxmd.com/read/24472875/23na-magnetic-resonance-imaging-of-the-human-lumbar-vertebral-discs-in-vivo-measurements-at-3-0-t-in-healthy-volunteers-and-patients-with-low-back-pain
#16
Stefan Haneder, Melissa M L Ong, Johannes M Budjan, René Schmidt, Simon Konstandin, John N Morelli, Lothar R Schad, Stefan O Schoenberg, Ulrich H Kerl
BACKGROUND CONTEXT: 1H magnetic resonance imaging (MRI) of the spine can rule out common causes of low back pain (LBP), such as disc protrusions or nerve root compression; however, no significant causal relation exists between morphology and the extent of symptoms. Functional MRI techniques, such as 23Na, may provide additional information, allowing indirect assessment of vertebral glycosaminoglycan concentrations, decreases in which are associated with early degenerative changes. PURPOSE: To evaluate 23Na-MRI of asymptomatic healthy volunteers and symptomatic patients with LPB and correlate the results to the Pfirrmann classification of MRI disc morphology...
July 1, 2014: Spine Journal: Official Journal of the North American Spine Society
https://www.readbyqxmd.com/read/24350659/a-23na-magic-angle-spinning-nuclear-magnetic-resonance-xanes-and-high-temperature-x-ray-diffraction-study-of-nauo3-na4uo5-and-na2u2o7
#17
A L Smith, P E Raison, L Martel, T Charpentier, I Farnan, D Prieur, C Hennig, A C Scheinost, R J M Konings, A K Cheetham
The valence state of uranium has been confirmed for the three sodium uranates NaU(V)O3/[Rn](5f(1)), Na4U(VI)O5/[Rn](5f(0)), and Na2U(VI)2O7/[Rn](5f(0)), using X-ray absorption near-edge structure (XANES) spectroscopy. Solid-state (23)Na magic angle spinning nuclear magnetic resonance (MAS NMR) measurements have been performed for the first time, yielding chemical shifts at -29.1 (NaUO3), 15.1 (Na4UO5), and -14.1 and -19 ppm (Na1 8-fold coordinated and Na2 7-fold coordinated in Na2U2O7), respectively. The [Rn]5f(1) electronic structure of uranium in NaUO3 causes a paramagnetic shift in comparison to Na4UO5 and Na2U2O7, where the electronic structure is [Rn]5f(0)...
January 6, 2014: Inorganic Chemistry
https://www.readbyqxmd.com/read/24240197/transient-compartment-like-syndrome-and-normokalaemic-periodic-paralysis-due-to-a-ca-v-1-1-mutation
#18
Chunxiang Fan, Frank Lehmann-Horn, Marc-André Weber, Marcin Bednarz, James R Groome, Malin K B Jonsson, Karin Jurkat-Rott
We studied a two-generation family presenting with conditions that included progressive permanent weakness, myopathic myopathy, exercise-induced contracture before normokalaemic periodic paralysis or, if localized to the tibial anterior muscle group, transient compartment-like syndrome (painful acute oedema with neuronal compression and drop foot). 23Na and 1H magnetic resonance imaging displayed myoplasmic sodium overload, and oedema. We identified a novel familial Ca(v)1.1 calcium channel mutation, R1242G, localized to the third positive charge of the domain IV voltage sensor...
December 2013: Brain: a Journal of Neurology
https://www.readbyqxmd.com/read/24139955/the-na-transport-in-gram-positive-bacteria-defect-in-the-mrp-antiporter-complex-measured-with-23na-nuclear-magnetic-resonance
#19
Kamil Górecki, Cecilia Hägerhäll, Torbjörn Drakenberg
(23)Na nuclear magnetic resonance (NMR) has previously been used to monitor Na(+) translocation across membranes in gram-negative bacteria and in various other organelles and liposomes using a membrane-impermeable shift reagent to resolve the signals resulting from internal and external Na(+). In this work, the (23)Na NMR method was adapted for measurements of internal Na(+) concentration in the gram-positive bacterium Bacillus subtilis, with the aim of assessing the Na(+) translocation activity of the Mrp (multiple resistance and pH) antiporter complex, a member of the cation proton antiporter-3 (CPA-3) family...
January 15, 2014: Analytical Biochemistry
https://www.readbyqxmd.com/read/24081646/in-vivo-sodium-23na-imaging-of-the-human-kidneys-at-7-t-preliminary-results
#20
Stefan Haneder, Vladimir Juras, Henrik J Michaely, Xeni Deligianni, Oliver Bieri, Stefan O Schoenberg, Siegfried Trattnig, Štefan Zbýň
OBJECTIVE: To evaluate the feasibility of in vivo (23)Na imaging of the corticomedullary (23)Na gradient and to measure (23)Na transverse relaxation times (T2*) in human kidneys. METHODS: In this prospective, IRB-approved study, eight healthy volunteers (4 female, 4 male; mean age 29.4 ± 3.6 years) were examined on a 7-T whole-body MR system using a (23)Na-only spine-array coil. For morphological (23)Na-MRI, a 3D gradient echo (GRE) sequence with a variable echo time scheme (vTE) was used...
February 2014: European Radiology
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